Angle of inclination of the articular surface of the distal radius.

Measurements on 57 normal radiographs of the wrist were performed twice by the same observer in order to determine the intra-observer variance. Measurements of the volar tilt (average 12 degrees), the radial angulation (average 23 degrees) and the length of the radial styloid (average 12 mm) had a reproducibility of 21%, 9% and 6% respectively. It was concluded that a good lateral radiograph, clearly outlining the articular surface, is important for the reproducibility of the measurements. In the AP plane the length of the radial styloid should be used as a measure of dislocation when evaluating fractured wrists, since the latter is easier to determine and gives the same information as the radial angulation.